The present invention relates generally to a suspension system for a sliding door, and more particularly to an improved suspension system for a heavy sliding door, such as may be used in penal institutions.
Other sliding door suspension systems have been used to suspend such heavy doors from above. One known system uses a horizontal trough mounted along an upper edge of the door frame. The door is suspended from a roller assembly which rolls within the trough to slidably open and close the door. To provide smooth operation of the door, the roller is shorter in axial length than the width of the trough. This feature disadvantageously allows for excessive inward and outward movement of the door, that is, movement in a direction perpendicular to the direction in which the door opens and closes. This excessive inward and outward motion of the door may prevent a door locking mechanism from engaging, thereby degrading the overall security and integrity of the sliding door assembly.
Another known sliding door suspension system has a rail made from a length of square steel stock, and a steel roller or wheel from which a sliding door is suspended. The roller has a radial groove machined therein which straddles the square steel rail which, as in the system mentioned above, also disadvantageously allows for excessive inward and outward movement of the door. Also, the steel to steel contact of the roller with the rail disadvantageously creates excessive noise when the door is opened and closed. The steel roller wears the rail, creating sharp edges which lacerate maintenance personnel during routine lubrication which is continually required. Also, the flat upper surface of the rail collects debris during construction of the facility, which may later interfere with the door operation.
Thus, a need exists for an improved sliding door suspension system for suspending heavy doors and for an improved sliding door assembly, such as may be used in penal institutions, which is not susceptible to the above limitations and disadvantages.